1. Field of the Invention
The present invention relates to power storage devices. In particular, the invention relates to a power storage device which stores power through reception of radio signals.
Note that “power storage device” as referred to in this specification means devices in general which store power through reception of radio signals from an external electric power supply device (a power feeder).
2. Description of the Related Art
Various electronic devices are coming into wide use and a wide variety of devices are on the market. In particular, in recent years, the spread of portable electronic devices has been marked. As an example, portable telephones, digital video cameras, and the like have become very convenient, having display portions with high definition, batteries that are more durable, and low power consumption. A portable electronic device has a built-in battery which is a power storage means. Thus, a power supply for driving the portable electronic device is secured from the battery. As a battery, a secondary battery (hereinafter also referred to as a “battery”) such as a lithium ion battery is used. As matters now stand, the battery is directly charged from an AC adaptor which is plugged into a household AC power supply, which is a power supply means (see Reference 1: Japanese Published Patent Application No. 2005-150022).
Note that in this specification, portable electronic devices having the battery of the invention are distinguished from other electronic devices which operate with power supplied from a fixed power source, and are referred to as “mobile electronic devices” (“mobile devices”).